Патент USA US3093753код для вставки
J1me 11, 1963 c. H. BLAKEWOOD ETAL 3,093,735 ENERGY STORAGE DEVICE Filed Jan. 22, 1960 4 Sheets-‘Sheet 1 l CONDUCTION BAND - l3 / /\__ - _ l5 IL / - __ __ _ - _ _ __ ._ - __ _ __ ELECTRON __ __ -_ l6 I - TRAPPING LEVEL SILVER THERMALLY EXCITED'HOLE TRAP —OPTICALLY EXCITED LEVEL HOLE TRAP LEVEL . 2 1 VALENCE ENERGY DIAGRAM BAND 24 Q\ 28 \ . \\ I \ / \ 2o 24 as \ ' \ ,/ \ \ / 20‘ € /26 >—/ 23 / NZ 1, N2 .L _ T // 2'“ / 25 \/ 52 I \ \ 2| / @’ ,2? / 5 1;‘ 29 3g L , N1 a‘ V ‘ -—25 23_J ."2 22 TRANS INVENTORS CHARLES H. BLAKEWOOD —1:—?- 3 A ‘ _ 08m“: W 81%;“ BY “Jim ' - _/ June 11, 1963 c. H. BLAKEWOOD ETAL 3,093,735 ENERGY STORAGE DEVICE Filed Jan. 22-, 1960 4 Sheets-Sheet 5 74 72 /73 78 N2 17 76 79 so‘ @ g B+ 1-@ INVENTORS . 'BLAKEWOOD W RSCHA UER June 11, 1963 3,093,735 C. H. BLAKEWOOD ETAL ENERGY STORAGE DEVICE Filed Jan. 22, 1960 4 Sheets-Shqet 4 \ 74 78 77' Y L 76 INVENTORS CHARLES H. BLAKEWOOD DOUGLAS M.WARSCHAUER BYDON DC. RE NOLDS L44. W'“ GEN United States Patent 0 " ice 3,093,735 Patented June 11, 1963 1 2 band, these electrons can make transitions to the valence 3,093,735 band, thereby emitting green light. ENERGY STORAGE DEVICE The next level 14 is the silver level which may or may Charles H. Blakewood, Baton Rouge, La., Donald C. Reynolds, Spring?eld, Ohio, and Douglas M. War not be present in the crystal. Electrons from the silver schaner, Newton Center, Mass, assignors to the United States of America as represented by the Secretary of the level may also make transitions down to holes in the Air Force transitions involve an emission of radiation of wave-length valence band, provided such holes are present. Such Filed Jan. 22, 1960, Ser. No. 4,581 7 Claims. (Cl. 250-83) (Granted under Title 35, US. Code (1952.), see. 266) of about 6000 angstroms. Other levels, depending upon the doping agent used, may exist in the crystal. The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to us of any level 15 and, the optically excited hole trap level 16. The next two levels are the thermally excited hole trap These two levels are characteristic of compounds made up from elements taken from group II and group VI in royalty thereon. This invention relates to an energy storage device cap the periodic table, for example, cadmium sul?de and cadmium-zinc sul?de compounds in their crystalline form. 15 These levels may yield electrons to the conduction band, in which case a hole is trapped in this level. able of storing energy for long periods of time. One object is to provide an energy storage device where in energy can be stored by irradiating the device with light up to 6900 angstroms. Another object is to provide an energy storage device 20 If a sample crystal, which is normally held at liquid nitrogen temperature, or about —-150 degrees centigrade, is warmed to a temperature between carbon dioxide temperature and room temperature, electrons are excited wherein the energy may be stored by thermal means. Another object is to provide a device wherein an in from the thermally excited level to the conduction band, leaving holes behind in the thermally excited level. The electrons in the conduction band contribute to electrical conduction across the sample if a voltage is applied. This dication of the stored energy may be produced by me chanical means. A further object is to provide a device wherein an indication of the stored energy may be produced by infra red irradiation. ' v conduction remains even after the source of radiation is removed and the sample is cooled back to the temperature . of liquid nitrogen. By mechanical tapping or illumination A still further object is to provide a device wherein the indication is in the form. of a change in conductivity. These and other objects will be more fully understood with infra-red energy between 9000 and 15,000 angstroms, the holes from the thermally excited level can be excited from the following detailed ‘description taken with the to the valence band so that the electrons in the conduction drawing wherein: band, which have been trapped in the electron trapping FIG. 1 shows an energy diagram for a material such as used in the device of the invention; light energy to stimulate the cell and mechanical tapping level, can make the transition from that level to the valence band. These transitions involve the emission of green light ‘and also a decrease in the conductivity of the sample. The axis along which the crystal is grown will to release the energy; hereafter be referred to as the C-axis and‘the release the FIG. 2 shows a device using a storage cell which uses ' energy the crystal must be tapped along this When the sample is illuminated with 6900 angstroms light, electrons are excited ‘from the optically excited hole’ trapping level to the conduction band from where they FIG. 3 shows a device similar to the device of FIG. 2 which uses an electro-mechanical transducer to provide the tapping; FIG. 4 shows a device similar to FIG. 2 which senses can make the transition to the valence band as described previously. The electrons in the electron trapping level FIG. 5 shows a device similar to FIG. 2 in which infra and the silver level can not make the transition to the red illumination is used to release the energy; FIG. '6 shows a device using a storage cell which uses 45 valence band unless there are holes present in the valence band. Thus holes trapped at 15 and 16 provide the thermal energy to stimulate the cell and mechanical tap the release of energy by the change in conductivity; ping to release the energy; ‘ storage effect. . , If the sample is doped with silver, electrons from the FIG. 7 is .a view along the line 7--7 of FIG. 6; FIG. 8 shows a device similar to FIG. 6 which senses silver level also make transitions down to holes in the the release of energy in the form of light in the range valence band, provided such holes are present, and such transitions involve the emission of red light of wave length of about 6000 angstroms. Light of other colors may be obtained with other doping agents. In FIGS. 2-5, light with wave lengths shorter than 6900 angstroms such between green and red in the visible spectrum; FIG. 9 shows a storage tube fusing the storage device of the invention; ’ FIG. 10 is a schematic showing of the storage screen of FIG. 9; ' 55 as ultraviolet light is used to stimulate the crystal and like elements in these ?gures are given like reference FIG. 11 shows the ‘device of FIG. 9 modi?ed to use, thermal energy to stimulate. the storage cells; FIG. 12 shows one possible storage unit which uses a ?ying spot scanner to illuminate the storage units. numbers. ‘FIG. 2 has a storage crystal 20 located with in a container '21 ‘on a block of copper 22. The crystal is cooled by liquid nitrogen 23. The crystal is stimulated by irradiating it with light of a wave length of 6900 Referring more particularly to FIG. 1 of the drawing wherein, reference number 11 refers to the conduction angstroms or shorter, from a source 24. After the illumi nation is removed, the crystal is tapped on the side 25 band in the energy diagram and 12 refers to the valence band. Between these two bands, four bands are shown, by a mass 26 which is suspended from a support 27. Movement of the .mass can be due to acceleration or rectly below the conduction band is the electron trapping 65 other means such as mechanical means or from the action to, and, from which various transitions are possible. , Di of an electro-rnagnet. When the mass strikes the side 25, a green light is given off which is sensed by a sens; level 13. Green light is emitted if an electron from this level makes a transition to the valence band. The wave ing unit 28 which may be a photomultiplier. In. length of this green light is approximately 5200 angstroms. an accelerometer, acceleration can be sensed by an out This level is in equilibrium with the conduction band, 70 put from sensing unit 28 due to the inertia of mass 26 which means that electrons in the conduction‘band may be trapped in this level and, if holes are present in the valence causing it to strilre face 25 after the crystal has been , stimulated. _ - - 3,093,725 4 The mechanical tapping can also be produced by an 9 modi?ed for use with thermal stimulation with like electromechanical transducer such as a piezo-electric transducer as shown in FIG. 3. In this device an electro elements being given like reference numbers. In this device the electrode 72 is spaced from cooling liquid 73 and connected thereto by means of straps 95. Otherwise put from sensing unit 23 due to the inertia of mass 26 in FIG. 2. The transducer 29 must be spaced at small distance from block 20 so as to provide the mechanical the device is the same as FIG. 9. ‘FIG. 12 shows a plurality of storage cells 99. These cells are stimulated by light from light source 100 which is modulated by a light modulating device 101 which In the device of FIG. 4 use is made in the change in may be a Kerr cell of electro-mechanical modulator and conductivity of the sample, when the light is given off due to the mechanical tapping, to produce an output sig 10 is scanned across the cells by a scanning device 102 which can be a mechanical scanner. The individual out nal. The output is taken off of electrodes 35 and 36. puts can be taken off of common lead 103 and individual It is obvious that the electro-‘mechanical transducer of leads 104. The information on the cells can be removed FIG. 3 could also be used with the device of FIG. 4. A by an infra-red light between 9000 to 15,000 angstroms few thousand ?ashes have been obtained with these de from source 105. vices and the conductivity of the sample changes after Though cooling means have been shown with all of each ?ash so that by applying certain predetermined sig the devices, no cooling means is needed when the device nals to the electro-mechanical transducer various shapes is operated in space as radiation from the cell will pro of output signals can be produced, for example, the con vide the cooling. ductivity can be made to change in a step manner by ap There is thus provided a storage cell capable of storing plying the signal to the transducer in the form of bursts. 20 energy for long periods of time. In the device of FIG. 5 infra-red radiation between While certain speci?c embodiments have been de 9000 and 15,000 angstroms is used to release the energy. scribed in some detail, it is obvious that numerous The green light given o?? is sensed by sensing unit 28 as changes may be made without departing from the general in FIG. 2. Light other than green may also be obtained principles and scope of the invention. by use of the proper doping agents. We claim: The devices of FIGS. 6-8 use thermal energy or very 1. An energy storage unit comprising: a crystal of long wave length infra-red energy applied for a time cadmium sul?de at the temperature of liquid nitrogen, suf?cient to heat the crystal to simulate the storage unit. means for illuminating said crystal with radiation with In the device of FIG. 6 a storage crystal 40 has two copper electrodes 41 and 42 located on opposite sides 30 a wave length shorter than 6900 angstroms, to thereby store energy therein, means for mechanically tapping thereof. A pool of liquid nitrogen 43 is supplied to cool said crystal along the C-axis of said crystal to thereby the crystal. Heat is conducted from the crystal by two release said energy and means for sensing the release of heat and electrically conductive support elements 44 and said energy. 45 and conductive support straps 46 and 47. The straps 2. An energy storage unit comprising: a crystal of 46 and 47 are very thin to permit the crystal to be heated cadmium sul?de, means for cooling said crystal to liquid and stimulated by the thermal energy from source 48 nitrogen temperature, means for illuminating said crystal passing through window 49, as shown in FIG. 7. A mass with radiation with a wave length shorter than 6900 50 similar to 26 in FIG. 2 and operated in a similar man angstroms, to thereby store energy therein, means for ner causes the crystal to give up light energy and change its conductance. An output is taken off of leads 51 and 40 mechanically tapping said crystal on a side perpendicular 52. An output in the form of green or other colored to the C-axis of said crystal to thereby release the stored light, depending upon the doping agent, could also be energy within said crystal in the form of green light and used with this device. means responsive to said green light for producing an out The device of FIG. 8 is similar to that of FIGS. 6 and put signal. 7 with like elements being given like reference numbers. 3. An energy storage unit comprising: a crystal of In the device of this ?gure, infra-red radiation from cadmium sul?de, means ‘for cooling said crystal to liquid source 60 illuminates cell 40 to release the energy and nitrogen temperature, means for illuminating said crystal the released energy in the form of green light is sensed with radiation ‘of a Wave length shorter than 6900 by :sensing unit 61 to produce an output at 62. It is angstroms, to thereby store energy therein, an electro obvious that the change in conductance could also be mechanical transducer located on a side of said crystal used with this device to obtain an output. perpendicular to the C-axis of said crystal, means for In the device of FIG. 9 the change in conductive prop applying a signal to said transducer to thereby release erties of the crystal are used in a storage tube. the energy within said crystal and means ‘for sensing the A cathode ray tube 70 has a screen 71 made up of release of said energy. storage elements as shown in FIG. 10 mounted within 4. An energy storage unit comprising: a silver doped the envelope. The storage elements are located on a crystal of a mixture of cadmium sul?de and zinc sul?de, heat and electrical conductive electrode 72 and is cooled means for cooling said crystal to liquid nitrogen tempera by liquid nitrogen 73. This screen can be made by secur ture, means for illuminating said crystal with ultra-violet ing large crystals to the copper plate with a conducting light to thereby store energy therein, an electro-rnechani bonding agent such as silver loaded plastic and then by 60 cal transducer located adjacent one of the sides of said etching or sand blasting the plate after a mask has been crystal perpendicular to the C-axis of said crystal, means placed over the crystals to thereby provide individual for applying a signal to said transducer to thereby release crystal of a size depending upon the resolution desired. the stored energy with said crystal in the form of green Certain of the cells are stimulated by an image of light light and means responsive to said green light for pro with wave lengths shorter than 6900 angstroms focused ducing an output signal. upon the screen by a lens 74. The conductivity of the 5. An energy storage unit comprising: a crystal con elements is sensed by a cathode ray beam from source sisting of a mixture of cadmium sul?de and Zinc sul?de, 76 which is scanned across the screen by deflection means for cooling said crystal to liquid nitrogen tem means 77 and 78 and an output is taken off at 79. The perature, means for illuminating said crystal with radia image can be erased either by tapping or by irradiation 70 tion with a wave length shorter than 6900 angstroms, to thereby store energy therein, an electro-mechanical trans with infra-red energy between 9000 and 15,000 ang ducer located adjacent one of the sides of said crystal stroms from source 80. When the image is erased a perpendicular to the C-axis of said crystal, means for light output signal is produced which may also be used applying a signal to said transducer to thereby release if desired. The device of FIG. 11 is similar to the device of FIG. 75 the energy within said crystal and means for sensing the tapping. 3,093,735 change in conductivity of said crystal when said energy is released. 6. An energy storage unit comprising: a crystal of cadmium sul?de, means for cooling said crystal to liquid nitrogen temperature, means for illuminating said crystal with radiation with a Wave length shorter than 6900 angstroms, to thereby store energy therein, an electro mechanical transducer located adjacent one ‘of the sides of said crystal perpendicular to the C-axis of said crystal, means for applying a signal to said transducer to thereby 10 release the energy within said crystal and means for sensing the change in conductivity of said crystal when said energy is released. 7. An energy storage ‘unit comprising: a cadmium sul?de crystal having a valence band, a conduction band, 15 a thermally excited hole trapping level and an ‘optically excited hole trapping level, means for cooling said crystal 6 C-axis of said crystal to thereby release the energy stored therein and means for sensing the release of said energy. References Cited in the file of this patent UNITED STATES PATENTS 2,031,884 2,234,328 2,546,160 2,692,950 2,739,243 2,761,070 2,902,605 2,920,205 2,93 6,373 2,990,473 3,031,574 Gray _______________ __ Feb. 25, Wolff _______________ __ Mar. 11, Lengyel ____'_ ________ __ Mar. 27, Wallace _____________ __ Oct. 26, Sheldon _____________ __ Mar. 20, Moos et al. __________ __ Aug. 28, Wallach _____________ __ Sept. 1, Choyke ______________ __ Jan. 5, Welker et al. _________ __ May 10, Kallmann ___________ __ June 27, Halsted _____________ __ Apr. 24, 1936 1941 1951 1954 1956 1959 1959 1960 1960 1961 1962 to a temperature of about -—150° centigrade, means for supplying energy to said crystal to raise electrons OTHER REFERENCES from one of said hole trapping levels to said conduction 20 Non-Destructive Sensing an Infrared Stimulable Phos band to thereby store energy therein, means for mechani phor, IBM Technical Disclosure Bulletin ‘of December cally tapping said crystal on a side perpendicular to the 1959, vol. 2, No. 4.